Microbiology Commons^™

Antimicrobial-Resistant Enterococcus In Urban Communities: Insights Into Human Infection Risks, Sumit Kumar Paudel

Wayne State University Dissertations

The complexity of community risk factors and transmission routes has been a major challenge to the containment of community-acquired antibiotic resistance. Possible factors range from environmental contamination, antibiotic misuse, and human exposure via animals, food, the environment, and human-to-human transmission. What has been missing from previous research is the integration of findings in animal and environmental sectors with bacteria implicated in community infections. To gain a better understanding of antibiotic resistance acquired in the community, a one health approach is clearly needed. Specifically, we aim to investigate the prevalence of antibiotic-resistant Enterococcus in wildlife, their gene profiles in comparison with …

Microbial And Plant Biodiversity In Appalachian Agroecosystems And Their Implications For Soil Health, Kinsey Reed Close

Graduate Theses, Dissertations, and Problem Reports (ETD)

The sustainability of agricultural landscapes depends on understanding the complex interactions between plants, soil, and microbes. In Appalachia, a region shaped by complex terrain and long histories of human and ecological interaction, small family farms produce hay, livestock, and row crops. These agroecosystems, though often treated as “artificial” by many ecologists, have the potential to support both food production and biodiversity conservation if managed with an understanding of ecological complexity. This dissertation examines how plant and microbial diversity interact with soil and management to influence nutrient cycling, soil health, and long-term resilience in Appalachian agricultural systems. A literature review revealed …

René Dubos: An Annotated Bibliography, Carol L. Moberg

René Dubos: An Annotated Bibliography

René Dubos (1901–1982), a prominent 20th century scientist, humanist, and philosopher, was a prolific author. Affiliated for more than 50 years with The Rockefeller Institute for Medical Research/The Rockefeller University, his studies ranged from antibiotics and the role of bacteria in human diseases to formulating broad ecological and environmental questions affecting human health and disease. His seminal writings explore a lifelong belief that a living organism—whether microbe, human being, society, or the Earth itself—could be understood only through its relationships with everything else.

This comprehensive bibliography of more than a thousand works by René Dubos includes brief annotations for each …

Impact Of Glufosinate On Soil Microbial Community Dynamics, Sarobi Das

Biology Dissertations - Archive

The increasing global regulations of glyphosate due to its possible carcinogenicity and environmental hazards have necessitated the search for alternative herbicides. Glufosinate-ammonium offers a sustainable attribute due to its low toxicity and limited reported herbicide resistance cases. Despite its increasing agricultural importance, very limited studies are done on its environmental impact, especially on the soil systems. This thesis examines the ecological behavior of glufosinate in soil, precisely focusing on its effect on the dynamics of soil microbiome and the potential use of Bradyrhizobium japonicum USDA110 for bioremediation by reversing the effect of microbial dysbiosis. A series of 30-day mesocosm studies …

Novel Infection By Mucor Hiemalis Kills Caenorhabditis Hosts Through Intestinal Perforation, Jay Ni

West Chester University Graduate Theses, Dissertations, and Final Projects

The nematode Caenorhabditis elegans has emerged as a popular model system to investigate cell biology and host-pathogen interactions. Presently, C. elegans is studied as a natural host of intracellular pathogens such as microsporidia and Orsay virus along with extracellular bacterial and fungal pathogens. The use of C. elegans as a model in host-pathogen research is limited by the number of naturally occurring pathogens to the organism. Through a sampling project to identify new pathogens of C. elegans, we identified the fungus Mucor hiemalis as a pathogen of Caenorhabditis species. We observed the fungus in the intestinal lumen of wild-caught …

Clonal Variation In Effector Gene Expression As A Mechanism For Pathogenic Adaptation In Magnaporthe Oryzae, Rebekah J. Ellsworth

Theses and Dissertations--Plant Pathology

Magnaporthe oryzae is a filamentous fungal pathogen that causes destructive diseases in cereals, including rice blast, wheat blast, and gray leaf spot. It is responsible for 10–30% annual yield losses in rice (Nalley et al., 2016) and up to 100% loss in wheat under favorable conditions (Kohli et al., 2011). Disease management typically relies on the use of resistant cultivars, but M. oryzae rapidly overcomes host resistance by mutating or deleting avirulence (AVR) genes recognized by host immune receptors. This rapid adaptation, often occurring within one to two growing seasons, presents a major challenge to breeding for durable resistance.

The …

Genetic Analysis Of Methionine Restriction-Associated Mitochondrial Unfolded Protein Response Signaling., Josh D. Dodge

Biology Dissertations - Archive

The lifespan of an organism is dictated by various genetic and environmental factors. One such determinant is the health of mitochondria which are organelles that mediate various critical cell functions including a significant role in generating the vast supply of cellular energy. Indeed, the gradual decline of mitochondrial function is believed to be a hallmark and possible cause of aging. Paradoxically, mild mitochondrial dysfunction early in life extends lifespan in various model organisms. Cells use diverse approaches to promote mitochondrial homeostasis, including the transcriptional reprogramming of cells by mitochondrial unfolded protein response (UPRmt) to mitigate mitochondrial stress. Consistently, UPRmt activation …

For Dust Thou Art, And Unto Dust Shalt Thou Return — Testing Soil-Derived Plant-Beneficial Bacteria For Potential As Biofertilizers, Johnathon Brim, Blake Oler, Jacob Hardy, Joseph Richardson, Ryan Bjazevich, Kate Whalen, Emmelia Wevers, Foxx Naylor, Ethan Shreeve, Alex Cherry, Ethan Cherry, Tanner Gunnell, Jayden Longhurst, Andrew Burrows, Mailon Odell, Jacob Sy, Jeffrey Schacterle

Library/Life Sciences Undergraduate Poster Competition 2025

• The results of plant testing have shown that bacteria treated seeds outperform the control seeds on a consistent basis
• We will continue to receive more data from out own experiments as well as crowdsourcing methods.
• Our next step is to begin comparing results of our soil/seed treatment against commercially available fertilizers that use beneficial bacteria.

Unveiling The Bacterial Communities Of Aphaenogaster: Taxonomic Composition, Developmental And Species Influences, And The Impact Of Climate Change, Lily Kelleher

West Chester University Master’s Theses

Ants are vital keystone species in many ecosystems because they provide ecosystem services such as: seed dispersal, soil bioturbation, and pest control. However, ant bacterial symbioses remain largely unstudied, but these interactions are crucial because microbes play a vital role in the ants’ overall health. Today, global climate change is impacting our biodiversity, and we can use information about how changing temperatures impact the symbiotic bacterial communities associated with ants to predict future impact. Aphaenogaster rudis and A. fulva remain understudied in terms of their bacterial community and are important North American species. For this study, ants from several colonies …

Parallel Inquiries: Investigation Of Social Resource Use In Early Career Stem Teachers And Impacts Of Metal Pollution On Fingernail Clam Microbiome, Emily Hamada

EWU Masters Thesis Collection

No abstract provided.

The Role Of Horizontal Gene Transfer In Antibiotic Resistance Amidst Prevalent Community And Healthcare-Associated Mrsa Rates, Gabrielle Nascimento

Honors College Theses

In recent decades, cases of community-acquired MRSA (CA-MRSA) and healthcare-associated MRSA (HA-MRSA) have been on the rise. The ability of antibiotic resistance to transfer between microorganisms greatly expands its threat to the effective treatment and containment of bacterial infections. The mecA gene is found on a mobile cassette within the Staphylococcal cell and encodes for PBP2a, an alternate version of penicillin-binding protein (PBP) with less binding affinity for β-lactam antibiotics, increasing resistance to the effects of antibiotics. The goal of this research is to investigate the horizontal transfer of the mecA gene between various Staphylococcus species as well as to …

Analysis Of The Microbiome Of Amblyomma Americanum In The Statesboro Region, Ella Zierdt, Lorenza Beati, Mary Humphrey, Saviour Dralabu

Honors College Theses

The lone star tick, Amblyomma americanum, is the most common tick in Georgia. It is mainly known as an Ehrlichia spp. vector, but its microbiome can be diverse, depending on geography, developmental stage, and season. Little is known about bacterial diversity in ticks from the southeastern U.S. A Nanopore MinION sequencer was used for a preliminary analysis of the bacterial microbiome in A. americanum from the Statesboro region. DNA was extracted from 39 nymphs, 35 males, and 39 females. DNA samples were pooled by month of collection and life stage/sex, amplified with barcoded 16SrDNA primers, and sequenced. Approx. 77% …

Effects Of Liraglutide On The Gut Bacterial Community, Jami Anne Bull

Graduate Theses/Dissertations

Overweight and obesity are major health concerns associated with metabolic disorders and gut dysbiosis. Treatment options such as GLP-1 receptor agonists, like liraglutide, promote weight loss and improve insulin sensitivity; however, their impact on the gut bacterial community remains unclear. This study investigated the effects of liraglutide on the gut bacterial community of diet-induced obese (DIO) mice using Illumina DNA sequencing of the bacterial 16S rRNA gene. My study used twelve-week-old male C57BL/6J DIO mice. They were placed on a high-fat diet and treated with liraglutide (0.2 mg/kg) via daily subcutaneous injection for 14 Days. High-fat and low-fat diets control …

Inoculating Soybean Plants At Different Growth Stages: Selecting Bradyrhizobium, Sinorhizobium, Or Both, Matthew R. Knoll

Graduate Theses/Dissertations

Soybean plants rely on nitrogen for growth, however atmospheric nitrogen (N2) is not a usable form and needs to be converted into different forms that are available to the plant. Nitrogen fixing bacteria such as rhizobia form symbiotic relationships with Soybeans in exchange for shelter and excess plant sugars. As a result, the plant can get the nitrogen it needs. There are four main genera of rhizobia that can form root nodules on Soybean including Bradyrhizobium, Sinorhizobium, Mesorhizobium, and Rhizobium. At this point, the effect that age of the host plant has on the selection of …

Ribomoe: An Application Of Mixture Of Experts On Artificial Riboswitch Classification, Hainian Audrey Long

Master's Projects

Urban water sewage is a potential health concern due to its possibility to spread contagious RNA viruses such as Coxsackievirus B3. However, detection of viral particles remains challenging because of low viral concentrations in wastewater and high mutation rates of the RNA virus. To address this, this study proposes a novel viral detection method using synthetic riboswitches that bind to the target virus and trigger a reporter gene, amplifying the detection signals. To support the design of effective riboswitches, we present a machine learning model for classifying riboswitch performance, integrating RNA sequence data with secondary structural features. This model used …

Spermidine And Polyamine Blockade As Key Mediators Of Intestinal Epithelial Cell Functions, Madison Lynn Flory

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Frequently, alterations in the composition of the gut microbiota and its metabolites are linked with intestinal diseases, including inflammatory bowel disease and colorectal cancer. However, the direct connections between alterations in the microbiome and disease states often remain elusive. Prior research has identified increases in both polyamines, which are a class of microbial metabolite, and in the abundance of bacteria that can produce polyamines, in a murine colorectal cancer model. Understanding the significance of the interaction between these microbial metabolites and intestinal epithelial cells (IECs) will provide new and expanded evidence of the importance of the gut microbiome in colorectal …

Characterization Of A Highly Arsenic-Resistant Microbe, Eleanor E. Windholz

Honors Theses

Heavy metal pollution in our terrestrial and aquatic ecosystems is a major global concern, as chronic exposure to heavy metals such as arsenic and chromium has dire effects on mammalian health. In these polluted, arsenic-rich environments, microorganisms resistant to heavy metals have been isolated. The microbe isolated in this paper was resistant to As(V) up to 1100 mM, which is significantly higher than most published strains, and resistant to Cr(VI) at concentrations up to 5 mM. The microbe was tentatively identified as Micrococcus luteus, but its high arsenic resistance suggests it may be a novel strain. The ability of the …

Investigation Of Hydrogen Gas Production And Motility In Δselab And Δfdhf Mutants Of Clostridioides Difficile, Ria D. Gupta

Honors Undergraduate Theses

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium and the leading cause of antibiotic-associated diarrhea worldwide. During infection, antibiotic-induced disruption of the gut microbiota allows C. difficile to colonize and proliferate. Motility, enabled by flagella, is an important factor in colonization and may be influenced by metabolic activity. Recent experiments have observed gas production during C. difficile motility assays, but the biochemical basis of this phenomenon remains unknown. Because gas formation in other bacteria such as E. coli involves the formate hydrogenlyase complex and the enzyme formate dehydrogenase (FDH), we hypothesize that C. difficile gas production under motility conditions is …

Assessing The Role Of Daily Thermal Fluctuations In The Performance Of Mitochondrial Energy Transduction Of The Centrarchid, Lepomis Cyanellus, Grayson Hofmann

Masters Theses

Freshwater systems are affected by current climate extremes, forcing species found in these systems to withstand drastic changes in temperature. Temperature changes affect these organisms by altering their metabolic rate and energy balance. Increases in temperature can lead to an increase in oxygen consumption, which ultimately increases the need for more energy production. Mitochondrial energy transduction of green sunfish (Lepomis cyanellus) and many other fish species after a thermal insult, has hardly been explored. This study complements the limited research available on mitochondrial function in similar species, as they ignore the possibility of consecutive thermal events, which are …

Functional Characterization Of The Hdt5 Gene In Aspergillus Flavus Morphogenesis, Mycotoxin Production, And Fungal Phytopathogenicity, Brenda Omburo

Graduate Research Theses & Dissertations

The present study aimed at elucidating the role of hdt5 in fungal morphology, mycotoxin production and in plant virulence in Aspergillus flavus. Currently, methodologies to prevent the negative impact of A. flavus are insufficient. It is known that expression of the hdt5 gene is dependent on hbx1, a master regulatory gene that affects expression of hundreds of genes in the A. flavus genome, controlling both development and secondary metabolism. However, while the aflatoxin gene cluster has been elucidated, the genetic regulatory mechanisms controlled by hdt5 are not fully understood. For this study, therefore, a complete strain set composed of a …